Flooding point diagram

To use the flooding point diagram, first it is necessary to decide whether the drops produced in the extractor are circulating or oscillating. The mean diameter di,2 (see Eq. 9.1) is used for the characteristic drop size. If the flow rate ratio is known from the thermodynamic design, the superficial velocities of both phases can be determined at the flooding point. The minimum column cross-sectional area and diameter necessarily follows directly from the superficial velocity at the flooding point with Eq. 9.19. 

Fig. 9.13 Flooding point diagram of countercurrent extractors. The drawn lines for six different Ar values are valid for circulating drops. The dotted lines for three different values are valid for oscillating drops. (From Ref. 2.)... 

Fig. 9.14 Flooding point diagram of centrifugal extractors (see Fig. 9.9). Curve 1 marks the lower limit, when the rotor is filled with heavy phase curve 2 marks an upper hmit, when the rotor is filled with light phase curve 3 marks the limit of the total throughput of both phases.

For sizing the gas circulating pump, feed pump and reflux pump the results of the optimizations were used. TTie determination of the maximum flows was based on a flooding point diagram. As an example, the optimization of the Monoglyceride process required a gas flow of the regenerated C02/C3Hg mixture of... 

Figure 2.2-9 Flooding point diagram for countercurrent gas-liquid flow [12] after Billet [13]. The lines mark the upper limit of gravity driven countercurrent flow. Under usually operating conditions, 80% of that limit can be used.

Mersmann s [3] flooding point diagram describes the flooding in packed columns for small packing elements with d < 25 mm sufficiently accurately throughout the entire... 

The flooding point diagram, developed by Mersmann, uses the falling or rising velocity ws of an individual droplet as a parameter. Acc. to Fig. 7-14, the ordinate axis shows the dimensionless volumetric flow rate of the continuous phase... 

Figure 7-17 [15] shows a comparison between the experiment and the calculated flooding point data, Eq. (7-21), with the parameter m= 1.9 for pure binary mixtures and ternary mixtures C D and for the mass transfer direction D C with the parameter m = 1.5. As can be seen from the comparison, the experimental data has been verified by calculation with an accuracy of less than 20 %. It was therefore possible to significantly consolidate and generalise the information available on the loading capacity of non-pulsed extractors, compared to Mersmann s flooding point diagram shown in Fig. 7-14. 

The column diameter of the extractor can be determined using the flooding point diagram, acc. to Fig. 7-16 and Eqs. (7-19) and (7-21). Curve 1, with the parameter m = 1.9, apphes to the transfer direction C D and to pure binary mixtures as well as to random and structured packings as well as tube columns ofvarious types and sizes. The operation of packed column below the loading line uc < 0.65 - ucjq is recommended. 

Figure 2-11 shows a diagram of the correlation between the liquid hold-up hp and the gas velocity uy. The correlation for h pj was derived, based on the following assumptions (duy/9/z ) = 0 at the flooding point for up = const. 

Table 2-6. Data relating to the experimental flooding point values, diagrammed in Fig. 2-17a, in columns with randomly filled metal packing elements. No. of test system acc. to Table 2-2...

Mersmann (1980) [17] has developed a graphic model for determining the specific flow rate of the dispersed phase at the flooding point, using a capacity diagram, see Fig. 7-14, which is applicable to any types of packings, packing structures and materials. 

Figure 7-16. Flood load diagram according to Mersmann [15], modified by Mackowiak with own test points and [6, 9,11-14]. Symbols see Table 7-4...

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